Investigation of aquaculture components for increased ... · R. Gieschen, J. Landmann, N. Goseberg,...

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| Rebekka Gieschen, Jannis Landmann, Nils Goseberg, Arndt Hildebrandt |

| FZK Kolloquium 2019 | 21.03.2019 |

Leichtweiß-Institut für Wasserbau

Abteilung Hydromechanik, Küsteningenieurwesen und Seebau

Investigation of aquaculture components for increased

efficiency

R. Gieschen, J. Landmann, N. Goseberg, A. Hildebrandt | FZK Kolloquium | Seite 2

Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


Introduction - Background

• Overall, increasing demand for

aquatic products

• Bivalves an essential source of

proteins

• Aquaculture is one of the fastest-

growing sectors for protein-based

food

FAO; 2016



• Aquaculture near-shore faces

different challenges:

• Stakeholder conflicts

• Nutrient depletion

• Changes in species assemblage

• Marine litter

• Perspective move to offshore

location to offset deficits

• Challenging conditions have to be

accounted for

Marlborough District Council; 2018

Goseberg, N; 2017



• Hydrodynamic forces acting on fixed

and floating structures commonly

investigated

• Existing research related to

shellfish aquaculture is scarce

• e.g. Buck, B.H.; Stevens, C.;

Plew, D. R.

• Little research available regarding

physical laboratory tests of shellfish

aquaculture

Bradshaw, P; 1965 Plew, D.R.; 2005

Marine Farming Association; 2017


Introduction - Objectives

• Investigation of wave-current forcing

on aquaculture structures

• Basic research regarding

motion and forces of mussels /

mussel-encrusted lines

• Project research of

„revolutionary“ aquaculture

designs

• Determination of response of

structure to waves and currents

• Assessment of survivability of

structures in extreme conditions

Vitasovich, P.; 2017

Goseberg, N.; 2017


Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


Live Mussel tests

• Collection from aquaculture farm

close to Kiel,Germany

• 3.62 m dropper line of Baltic Blue

Mussels

• Transport & storage in aerated

tank with Baltic Sea water

Landmann, J.; 2017


Live Mussel tests

• Portioned in three specimens (~1 m)

• Data acquisition

• Per specimen

• For single mussels

• For each specimen determination of

• Weight

• Length

• Width every 5.0 cm

• Displacement

• Bending stiffness

Landmann, J.; 2017


Live Mussel tests

• Methodology:

• Determination of drag and inertia coefficients

• Current (Drag) & Wave tests

• Morison equation: 𝐹 = 1

2𝜌𝐶𝐷𝑢

2𝐴 + 𝜌𝐶𝑀𝑉𝑢

Landmann, J; 2017


Live Mussel tests

• Mounting frame fitted with:

• 6-axis-force transducer

• Ultra-sonic wave gauges

• Acoustic Doppler Velocimeter

• Carriage fitted with:

• Incremental rotary recorder

• Webcam

• Underwater camera

Landmann, J; 2017


Live Mussel tests

• Drag tests with four velocities

• 𝑅𝑒 = 𝑢∗𝐷𝑖

𝜈

• 𝑅𝑒 = 2.0 × 104 to 1.1 × 105

• Top- and bottom-mounted

• Test for load-evasion potential of

dropper lines

• ~80% force reduction

Landmann, J; 2017


Live Mussel tests

• Calculation of 𝑪𝑫-values:

• Levels about CD = 1.6 after initial drop

• Little changes in CD for higher Re-Numbers

Hild

ebra

ndt

et al.,

2018


Live Mussel tests

• Inertia tests with three waves

• 𝐻𝑠 = 0.1 𝑚, 0.12 𝑚, 0.15 𝑚

• 𝑇𝑝 = 1.2 𝑠, 2.4 𝑠, 1.65 𝑠


• Test for load-evasion potential of

dropper lines

• ~80% force reduction

• 𝑪𝑴-values: In progress

Top- and bottom-mounted

Top-mounted

Landmann, J; 2017


Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


Surrogate creation

• Aim is to create object with

similar characteristics in

currents and waves as live

mussels

• Assuming that CD and CM are

influenced by surface geometry

• Evaluation via Abbot-Firestone-

Curve

• Describes surface texture of

an object

• Material distribution as a

function of depth Ongsiek, T..; 2017



Surrogate creation

• Concept 1:

• Based on single mussels

• Concept 2:

• Closest fitting 3D-scanned

section to mean AFS

• Concept 3:

• Perfect fit to Abbot-Firestone

Curve with simplified

geometry

Surface Portion [%]

Dia

mete

r [m

m]

Surface Portion [%]

Dia

mete

r [m

m]

Surface Portion [%]

Dia

mete

r [m

m]

Ongsiek, T..; 2017


Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


1:1 Single surrogate tests

• Methodology:

• Determination of drag coefficients

via current tests

• Tests with seven velocities:

• 0.1𝑚

𝑠, 0.25

𝑚

𝑠, 0.35

𝑚

𝑠, 0.50

𝑚

𝑠,

0.75m

s, 1.00

m

s, 1.20

m

s

• 𝑪𝑫-values: In progress

Ongsiek, T..; 2017

Landmann, J..; 2017


1:1 dropper line surrogate tests

• Same tests as live mussels

• Drag tests with four velocities

• Inertia tests with three waves


• Evaluation regarding inertia and

drag coefficients

• Comparison to live-mussel data

• 𝑪𝑫- and 𝑪𝑴-values: In progress

Landmann, J.; 2017

Landm

ann e

t al., 2019 [

in p

rep.]


Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


Surrogate 1:X tests

• Scaled surrogates

• 1:4, 1:10 and 1:16 with geometric similarity

• Concept 2 dismissed

Landmann, J; 2017 Landmann, J; 2017

Gie

schen e

t al., 2019 [

in p

rep.]


Surrogate 1:X tests

• Methodology

• Wave tests only

• Determination of drag and inertia coefficients

• Investigate scaling effects on coefficients

• Determination of limits of down scaling

Landmann, J; 2017


Surrogate 1:X tests

• Mounting frame fitted with:

• 2-axis force transducer

• Ultra-sonic wave gauge


• Sensor set-up change for top mounted only

• Test for load-evasion potential ~90 %

• Inertia tests with 5-7 waves each

• Froude-Scaling of waves from live mussel

tests

• CD, CM and scalability: In progress

Landmann, J; 2017


Basic Research

Live Mussel tests

Surrogate creation

Surrogate 1:1 tests

Surrogate 1:X tests

Farm concepts

Long-Line System

Outline


Long-Line System

• Structure

• „Traditional“ system in NZ

• Objective

• Novel measurement concept

regarding the mooring forces and

accelerations

• Influence of mussel dropper lines

on force evolution under waves and

currents

• Motion response of the system

under waves and currents


Goseberg, N.; 2017


Long-Line System

• Methodology

• Wave spectra and

• 5 Wave sets:

• Height 1.2 – 25 cm

• Period 0.76 – 2.9 s

Goseberg, N.; 2017

Landmann, J.; 2018

Landmann, J.; 2018


Long-Line System

• Mooring Forces

• Added mass of mussels

increases tension

• Submerged system

experiences higher loads

due to pretension

• Snapping loads present

Landm

ann e

t al., 2019


Long-Line System

• Accelerations

• Mussels dampen

acceleration due to

hydrodynamic mass

• Submerged system

experiences lower

accelerations

• Positive implications

regarding drop-off

Landm

ann e

t al., 2019


Long-Line System

• Numerical Simulation

• OrcaFlex-Model

• Validation with experimental data

• Parametric study planned

Fröhling, L.; 2019

Fröhling, L.; 2019

Fröhling, L.; 2019


Discussion

Investigation of aquaculture components for increased ... · R. Gieschen, J. Landmann, N. Goseberg,...

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